1. Field of the Invention
The instant disclosure relates to a light emitting diode (LED) package; in particular, to a chip-on-board (COB) LED package.
2. Description of Related Art
Comparing the light-emitting diode (LED) to the traditional light source, LED is smaller in volume, energy saving, better light efficiency, longer lifespan, fast in response, and without producing heat radiation or poisonous mercury. Thus, LED has been widely used in recent years. The conventional illumination module is usually in a chip-on-board manner. For preventing the high temperature of the LED chips from affecting the overall efficiency, metal plate having desirable heat conductivity is adapted to facilitate heat dissipation. However, an insulation layer is usually disposed on the metal plate to electrically insulate the LED chips from the metal plate. The insulation layer is bad conductor of heat. Therefore, the insulation layer is poor in thermal resistance. In addition, the process of electroplating silver is usually applied on the surface of the substrate to enhance the lighting efficiency of LED package in the conventional process. However, electroplating silver results in sulfurization, and the sulfurization leads to degradation of light. Therefore, the life span of the product is decreased.